An engine has a balance shaft module (BSM) for dampening vibrations of the engine. The BSM has an idle gear assembly.
FIG. 1 is a perspective view of an engine having a BSM and an idle gear assembly.
Referring to FIG. 1, a BSM includes two balance shafts parallel to each other, and the balance shafts may be parallel to a crankshaft.
The two balance shafts respectively include balance gears 1 and 2.
The balance gears are a left balance gear 1 and a right balance gear 2.
At least one of the left and right balance gears 1 and 2 may be driven by being connected to the crankshaft with a chain or a gear.
In FIG. 1, the left balance gear 1 is driven by being gear-connected with a crank gear 3 mounted to the crankshaft.
To left and right balance shafts, balance weights may be mounted respectively, and the left and right balance gears 1 and 2 need to respectively rotate in opposite directions for balancing out vibrations of an engine.
An idle gear assembly 100 is disposed and engaged between a crank gear 3 and any one of left and right balance gears 1 and 2 such that the left and right balance gears 1 and 2 respectively rotate in opposite directions.
In FIG. 1, an idle gear assembly 100 is mounted between right balance gear 2 and a crank gear 3.
In the engine having a BSM, coated gears may be used for controlling backlash.
In order to control the backlash between the gears by using thickness of backlash control coating, the gears must be assembled in a condition of zero backlash at initial assembly of the gears with coating layer in between, and backlash control coating must vanish by abrasion in a short period of time while the engine operates and forms the backlash between gears.
If the backlash is not effectively controlled, abrasion and noise of the gears may be generated, more energy of driving gears is consumed than that in case of proper backlash control, and fuel consumption is deteriorated.
In addition, mounting problem may occur between a tool and an engine compartment, depending on a mounting position, when an idle gear assembly 100 is mounted to an engine.
For example, a jig space is necessary for fixing, when the idle gear assembly 100 is fixedly mounted inside a cylinder block.
Therefore, a mounting space of the idle gear assembly 100 may deteriorate the engine room compartment due to relations of position with other parts.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention, and therefore, it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.